<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <title>Online Judge</title>
    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.5.2/css/bootstrap.min.css">
    <style>
        body {
            background-color: #f8f9fa;
        }

        .hero {
            text-align: center;
            padding: 100px 0;
        }

        .hero h1 {
            font-size: 3em;
            font-weight: bold;
        }

        .hero p {
            font-size: 1.5em;
            color: #6c757d;
        }
    </style>
</head>

<body>
    <nav class="navbar navbar-expand-lg navbar-light bg-light">
        <a class="navbar-brand" href=" ">Online Judge</a >
        <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarNav"
            aria-controls="navbarNav" aria-expanded="false" aria-label="Toggle navigation">
            <span class="navbar-toggler-icon"></span>
        </button>
        <div class="collapse navbar-collapse" id="navbarNav">
            <ul class="navbar-nav">
                <li class="nav-item active">
                    <a class="nav-link" href="#">主页 <span class="sr-only">(current)</span></a >
                </li>
                <li class="nav-item">
                    <a class="nav-link" href="/all_problems">题目列表 </a >
                </li>
            </ul>
        </div>
    </nav>

    <div class="hero">
        <h1>欢迎使用蓝色空间号的在线评测系统</h1>
        <h6>鲜衣怒马少年时，不负韶华行且知</h6>

        <a class="btn btn-primary" href="/all_problems">开始练习</a >
    </div>

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</body>

</html>